/Engine/Source/Editor/VREditor/Public/UI/VREditorUISystem.h
Called when the user presses a button on their motion controller device
void OnVRAction ( class [FEditorViewportClient](API\Editor\UnrealEd\FEditorViewportClient) & ViewportClient, [UViewportInteractor](API\Editor\ViewportInteraction\UViewportInteractor) * Interactor, const struct [FViewportActionKeyInput](API\Editor\ViewportInteraction\FViewportActionKeyInput) & Action, bool & bOutIsInputCaptured, bool & bWasHandled )